Gregorian Telescope Claude Paris? C.1740

Beautiful Gregorian telescope mounted on a tripod base. In the main tube, a first steel mirror receives light (the image) which is then reflected and focused towards a second, smaller concave mirror. It is this image which is observed at the other end of the tube. An endless screw, installed along the tube, makes it possible to improve sharpness and vary the distance between the two mirrors. An additional tinted glass lens can be added for observing very luminous bodies. The first model of Gregorian telescope was built in 1673 in collaboration with the English physicist Robert Hooke (1635-1703). In the 18th century, Gregorian telescopes were found in many physics and curiosity cabinets.